CMX624 CML Microcircuits, CMX624 Datasheet - Page 21

• Manufacturer Part Number: CMX624
• Description: V.23-Bell 202 Modem
• Manufacturer: CML Microcircuits

V23 / Bell 202 Modem
Notes:
Notes:
Notes:
DTMF Transmitter
Tx Filter and Output Buffer
FSK Demodulator and Rx UART
2100Hz Detector
2001 Consumer Microcircuits Limited
‘Will Decode’ Frequency Range
‘Will Not Decode’ Frequency Range
‘Off’ to ‘On’ time
‘On’ to ‘Off’ time
Level at TOP pin; tones in High Group
Twist (level of High Group tones WRT level of
Tone frequency accuracy (worst case)
Change in level at TOP pin caused by changing
Buffer output signal swing;
Valid Input Level Range
Acceptable Twist (Mark level WRT Space level)
Acceptable Signal to Noise Ratio
Rx 1200bits/sec (V.23 mode)
Rx 75bits/sec (V.23 mode)
Rx 1200bits/sec (Bell 202 mode)
Rx 150bits/sec (Bell 202 mode)
Low Group tones)
Acceptable Rx Data Rate
Mark (Logical 1) Frequency
Space (Logical 0) Frequency
Acceptable Rx Data Rate
Mark (Logical 1) Frequency
Space (Logical 0) Frequency
Acceptable Rx Data Rate
Mark (Logical 1) Frequency
Space (Logical 0) Frequency
Acceptable Rx Data Rate
Mark (Logical 1) Frequency
Space (Logical 0) Frequency
bit 2 of FSK MODE Register
Load greater than 500 .
5. For each of the TXON (if enabled) and TXO pins, load between pin and V
6. Measured at point A in Figures 8a and 8b, for V
7. Flat noise in 300-3400 Hz band for V.23, 200-3400 Hz for Bell 202.
8. Set by Rx UART and Xtal frequency.
9. 2100Hz detection requires a signal within the amplitude range given in the Rx Energy
proportional to V
voltage gain of the Rx Input Amplifier should be adjusted by selecting the appropriate external
components as described in Section 1.6.1.
Detector section.
DD
. To cater for other supply voltages or different signal level ranges the
21
Notes
Notes
Notes
Notes
4
5
6
7
8
8
8
8
9
9
DD
<2010
-43.0
1188
1280
2068
1188
1180
2168
= 5.0V. The internal threshold levels are
2040
TBD
TBD
TBD
TBD
TBD
TBD
Min.
Min.
Min.
20.0
Min.
-1.0
-0.5
-7.0
2.5
2.2
4.0
-
-
1200
1300
2100
1200
1200
2200
Typ.
+2.0
Typ.
Typ.
Typ.
390
450
150
387
487
0.0
3.0
75
-
-
-
-
-
-
-
-
-
>2265
1212
1320
2132
1212
1220
2232
2235
Max.
Max.
Max.
Max.
+1.0
+0.5
+7.0
TBD
TBD
TBD
TBD
TBD
TBD
DD
-9.0
3.5
25
-
-
-
-
/ 2.
CMX624
D/624/6
Baud
Baud
Baud
Baud
dBm
Vp-p
dBm
Unit
Unit
Unit
Unit
ms
ms
dB
dB
dB
dB
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
Hz
%